A device configured to use a gas, such as a compressed natural gas or a hydrogen gas, is supplied with a fuel gas from a gas supply source of high pressure in light of the conveyance efficiency and the amount of storage, reduces the pressure of the supplied fuel gas up to working pressure or pressure equal to or lower than withstand pressure, and uses the obtained fuel gas. Therefore, a pressure reducing valve configured to reduce the pressure of the gas to the working pressure or the like is provided between the gas supply source and the device. One example of the pressure reducing valve is a pressure reducing valve described in PTL 1.
The pressure reducing valve described in PTL 1 includes a main body. An opening is formed in the main body, and a valve element is provided in the main body. The valve element is slidably supported by the main body and can perform a reciprocating movement between a closed position where the valve element closes the opening and an open position where the valve element opens the opening. The valve element receives secondary pressure toward the closed position, is biased by a spring toward the open position, and is located at a position where the acting force of the secondary pressure and the biasing force of the spring balance. On this account, the reduced secondary pressure is maintained at substantially constant set pressure corresponding to the biasing force of the spring.